1. Field of the Invention
The present invention relates a method of welding head-hardened rails in a rail-laying field.
2. Description of the Prior Art
Recently, there has been found an increased demand for rails having high strength, which has accompanied a tendency toward increased rapid rail transit and an increased railroad volume. As for these high-strength rails, there are included those made of alloy steel and those which have undergone heat treatment. Rails having their railheads alone heat-treated, which are so-called head-hardened rails, find wide acceptance because these are excellent in wear resistance and from an economy.
When rails which are not subjected to heat treatment are welded into a long rail, there have heretofore been adopted various rail welding methods, such as a thermit welding method. However, when the conventional welding methods, such as a thermit welding method, are applied to head-hardened rails, the railheads are tempered at their portions to be welded, have their hardness considerably lowered and lose their wear resistance. For this reason, welding of head-hardened rails, though desired to be carried out, has not materialized and, therefore, head-hardened rails of a given length have been used without giving any modification thereto.